Singh M, Krishnan R, Goswami B, Choudhury A D, Swapna P, Vellore R, Prajeesh A G, Sandeep N, Venkataraman C, Donner R V, Marwan N, Kurths J
Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India.
IDP in Climate Studies, Indian Institute of Technology, Bombay, India.
Sci Adv. 2020 Sep 18;6(38). doi: 10.1126/sciadv.aba8164. Print 2020 Sep.
Coupling of the El Niño-Southern Oscillation (ENSO) and Indian monsoon (IM) is central to seasonal summer monsoon rainfall predictions over the Indian subcontinent, although a nonstationary relationship between the two nonlinear phenomena can limit seasonal predictability. Radiative effects of volcanic aerosols injected into the stratosphere during large volcanic eruptions (LVEs) tend to alter ENSO evolution; however, their impact on ENSO-IM coupling remains unclear. Here, we investigate how LVEs influence the nonlinear behavior of the ENSO and IM dynamical systems using historical data, 25 paleoclimate reconstructions, last-millennium climate simulations, large-ensemble targeted climate sensitivity experiments, and advanced analysis techniques. Our findings show that LVEs promote a significantly enhanced phase-synchronization of the ENSO and IM oscillations, due to an increase in the angular frequency of ENSO. The results also shed innovative insights into the physical mechanism underlying the LVE-induced enhancement of ENSO-IM coupling and strengthen the prospects for improved seasonal monsoon predictions.
厄尔尼诺-南方涛动（ENSO）与印度季风（IM）的耦合对于印度次大陆夏季季风季节降雨预测至关重要，尽管这两种非线性现象之间的非平稳关系会限制季节可预测性。大型火山喷发（LVE）期间注入平流层的火山气溶胶的辐射效应往往会改变ENSO的演变；然而，它们对ENSO-IM耦合的影响仍不明确。在此，我们利用历史数据、25次古气候重建、过去千年气候模拟、大集合目标气候敏感性实验以及先进分析技术，研究LVE如何影响ENSO和IM动力系统的非线性行为。我们的研究结果表明，由于ENSO角频率增加，LVE促进了ENSO和IM振荡显著增强的相位同步。这些结果还为LVE引起的ENSO-IM耦合增强的物理机制提供了创新性见解，并加强了改进季风季节预测的前景。
